The French fleet forcing the entrance of Tagus River. 11 July 1831.

The French Fleet Forcing the Entrance of the Tagus from 1840 at Versailles documents a French naval action during the Portuguese civil wars. Vernet's naval paintings extended his military documentation to maritime subjects. Vernet's position as the official painter of the July Monarchy and later Second Empire gave him unparalleled access to military subjects, and his technique combined careful documentation with dramatic compositional flair. Horace Vernet, born into the most distinguished artistic dynasty in France and trained in the finest academic tradition, was the most commercially successful French painter of the first half of the nineteenth century. His military paintings, portraits, Oriental subjects, and biblical scenes were in continuous demand from the most powerful patrons in Europe, including King Louis-Philippe of France and Tsar Nicholas I of Russia. His enormous output — he was famous for the speed of his production — combined the technical facility inherited from three generations of painter ancestors with the Romantic sensibility and historical curiosity that defined the French art of his era.

The naval engagement is rendered with documentary precision and dramatic atmosphere. Vernet's handling of ships and water captures the maritime military action.